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-   -   Active rear wing test (https://www.miataturbo.net/race-prep-75/active-rear-wing-test-74913/)

Keith@FM 09-26-2013 11:53 AM


Originally Posted by Savington (Post 1056924)
That's what I assumed. It's one of the reasons the COT wing has never interested me - it's not designed for what we do in the slightest.

A gain of 2 seconds/lap on a 60 second track with a 50 mph average speed says it's doing something. So there's some overlap with what we do, even if it's not the ideal ultimate perfect option. Want me to test more wings? Send me more wings.


Originally Posted by cyotani (Post 1056935)
This type of thing is neat for FSAE projects since active aero isn't banned. I didn't read the whole thread (yet). But...

what was the change in the 100 to 0 stopping distance with the wing disabled and with it active?

Keep reading until you get to the part about the Traqmate data failure.

ThePass 09-26-2013 04:16 PM


Originally Posted by Keith@FM (Post 1057203)
A gain of 2 seconds/lap on a 60 second track with a 50 mph average speed says it's doing something. So there's some overlap with what we do, even if it's not the ideal ultimate perfect option.

Agreed. $350 for a full dry carbon wing that cost teams $3k when new, is tailored for low drag (a plus in my book), and that will produce significant downforce at our speeds, even if it works optimally at higher speeds? Win. Sure, you can spend a lot more to get something that's even more ideal, but it stands alone for cost : performance ratio.

-Ryan

triple88a 09-27-2013 01:22 AM

Keith, I wanna see a sucker miata. THAT will definitely help what we do.

Keith@FM 09-27-2013 11:17 AM

Please send money!

1993ka24det 09-28-2013 11:50 AM

--Ryan nice to see you back



Originally Posted by triple88a (Post 1057420)
Keith, I wanna see a sucker miata. THAT will definitely help what we do.

I looked into it abit, but not like the corvette with the Abrams exhaust fan. I was thinking of 2 120mm Ducted Fans from RC Planes. I knew that the fans are made for propulsion and not sucking, so start out with a small one then see the power of that one first.

dutchbag 09-28-2013 06:39 PM

You would need an order of magnitude more power than that to see any effect. A Miata-sized sucker would need 30-60 hp of air-moving power to generate a significant effect. You could probably feel something with 15hp and perfect sliding skirts.

'95MSM 09-28-2013 07:08 PM

Interesting project. In a discussion on ground effects for Sports2000 race cars, one of the true studs to ever race and/or engineer in the class gave a strong opinion that any gain in downforce is most likely wiped out by a loss in driver confidence - ground effects are so reliant on maintaining ride height, that you just won't have reliable grip braking into a corner due to brake dive changing the chassis height.

I offer this only to reinforce that the control system for a movable rear wing has to be absolutely reliable. The grip has to be there in every corner else the driver won't have the confidence to use it.

IIRC, the movable wings on the Chaparrals were controlled by a pedal, and returned to max downforce position when the pedal wasn't down. That was obviously a lot easier for the driver to manage since the cars used an automatic transmission, but a good fail-safe mode can't be under-valued.

I suppose the steering might go a little light if the max downforce mode was enabled at high speed. If you could tie-in movable front canards, the car could be kept balanced in either mode, just really draggy in fail-safe.

mr_hyde 09-29-2013 02:44 AM

Quick refresher please: Is the goal to move the wing to maximum downforce or past stall to use as an air brake?

I thought about this at our local track Thursday. T1 is a very fast left hander at the end of the straight (140+ to >100mph) followed 200 feet later by a ~60mph hard left up a steep incline. Discussing this with a few other drivers, we discovered some of us brake slowly and trail around to the T2 turn in and others brake hard into T1, maintenance throttle through T1 and brake again for T2. A front running spec could probably go flat through T1 and get shut down enough for T2.

In this scenario, a max downforce setting would probably be OK for either style but the air brake would be pretty scary for the trail braker when he realized the car was only stable in a straight line.

Keith@FM 09-30-2013 11:44 AM

This is an air brake, although it could be used to go to max downforce. Under max braking, the drag is more effective at slowing the car than downforce. It will also add stability to the car, the same way that throwing out a parachute will keep a car pointed straight. However, it won't add to cornering grip.

Yes, it will likely change the balance of the car under certain conditions. So the driver may have to adapt his line, the same way the line changes if you change horsepower significantly.

I'll be testing this weekend on a track that I know much better, and which includes a very interesting braking zone that is mid-corner. So we'll see how it works. That's why we test instead of just posting to the internet, to learn the truth of things. Well, it's why some of us test anyhow.

HeresJohnny 11-05-2013 03:18 PM


Originally Posted by Keith@FM (Post 1058223)
This is an air brake, although it could be used to go to max downforce. Under max braking, the drag is more effective at slowing the car than downforce. It will also add stability to the car, the same way that throwing out a parachute will keep a car pointed straight. However, it won't add to cornering grip.

Yes, it will likely change the balance of the car under certain conditions. So the driver may have to adapt his line, the same way the line changes if you change horsepower significantly.

I'll be testing this weekend on a track that I know much better, and which includes a very interesting braking zone that is mid-corner. So we'll see how it works. That's why we test instead of just posting to the internet, to learn the truth of things. Well, it's why some of us test anyhow.

Did similar to my MX5 in May, have a button on the wheel easy thumb reach for changing to air brake position. Thumb off back to downforce position. Worked well on the track...



Sorry no idea how to embed this vid into the forum :( thanks chap below for showing me how to 👍
Wished I'd thought of your brackets inside the boot wall.

Leafy 11-05-2013 03:21 PM

Randomly I discovered the motoIQ did this with their roof spoiler on their LeChump miata with a headlight motor a while ago as well. Kind of funny.

thenuge26 11-05-2013 03:53 PM

Not bad.

To embed a youtube vid, use the [ yt ] tags and keep only the gibberish letters: MuBmUr2qG3g


Rennkafer 11-05-2013 11:15 PM


Originally Posted by '95MSM (Post 1057885)
IIRC, the movable wings on the Chaparrals were controlled by a pedal, and returned to max downforce position when the pedal wasn't down. That was obviously a lot easier for the driver to manage since the cars used an automatic transmission, but a good fail-safe mode can't be under-valued.

Can't speak to the Chaparral but they did use a separate pedal in the Lotus 49 along with a clutch pedal. We had one in the shop with a high wing (active linkage not connected) but the pedal was still in the car.

triple88a 11-05-2013 11:43 PM


Originally Posted by thenuge26 (Post 1070559)
Not bad.

To embed a youtube vid, use the [ yt ] tags and keep only the gibberish letters: MuBmUr2qG3g

Not even, you can just post the link to the video as long as its a straight link.

http://www. youtube.com/ watch?v =X6r m5HSDy6g

mrdos 05-28-2014 12:43 AM

...So Keith did you ever get a chance to get any trackmate info on this? :)

mrdos 05-28-2014 12:56 AM

Also-a 60-0 or 100-0 test would be an easy way to tell how big the difference is. Since you have the override switch should be possible and take no time at all :)

Keith@FM 05-28-2014 07:43 AM

I spent the winter doing a fairly major rebuild on the car. No instrumented testing has been done yet.

krazykarl 05-28-2014 08:50 AM


Originally Posted by mrdos (Post 1134888)
Also-a 60-0 or 100-0 test would be an easy way to tell how big the difference is. Since you have the override switch should be possible and take no time at all :)

The true benefit wouldn't be known just by doing a quick back-to-back test. Since the wing will affect to some extent the amount of traction in the rear, for the test to fully reveal the benefit, you'd have to do several tests without it (or with it set at a constant AOA) while adjusting the brake balance until you find the best stopping time you can achieve with that setup. Then you enable the active wing, and do the whole thing again.

Without all that you'd just be getting an idea of how much aero-brake the wing gives, but you wouldn't know how much difference you'd get from having more (or possibly less, if the wing is fully stalled) rear traction.

triple88a 05-28-2014 11:49 AM


Originally Posted by Keith@FM (Post 1134909)
I spent the winter doing a fairly major rebuild on the car. No instrumented testing has been done yet.

You guys have winter there? :giggle:

mrdos 05-28-2014 12:30 PM


Originally Posted by krazykarl (Post 1134918)
The true benefit wouldn't be known just by doing a quick back-to-back test. Since the wing will affect to some extent the amount of traction in the rear, for the test to fully reveal the benefit, you'd have to do several tests without it (or with it set at a constant AOA) while adjusting the brake balance until you find the best stopping time you can achieve with that setup. Then you enable the active wing, and do the whole thing again.

Without all that you'd just be getting an idea of how much aero-brake the wing gives, but you wouldn't know how much difference you'd get from having more (or possibly less, if the wing is fully stalled) rear traction.

Point made, but as you mentioned it would give an idea of how much aero-brake the wing gives, which is somewhat the point and that would be an easy way to figure it out... Even with the method you described. Hell even that wouldn't really reveal the full benefit, as you don't go 100-0 in a race, 100-60 is a more like it... However the point would be to see how much stopping power the wing gives, how much help on track is an entirely different matter.


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